Rigid-disk files consist of a stack of one or more circular disks having a thin magnetic coating which are rotated at a high angular velocity. Data is recorded on the disk surfaces using heads or transducers mounted on long arms that are moved across the disk surfaces by a high-speed actuator. Information is actually recorded on circumferential tracks located on the disk surface. Reading the recorded information back involves sensing the magnetic transitions emanating from the surface of the disk by means of the read/write elements.
In recent years there has emerged a discernible trend in the magnetic recording industry toward thin-filmed head designs. Thin-film heads provide high-precision, multiple-track recording capabilities with high-bit and high-track densities. Thin film head designs also reduce the number of customized fabrication steps required to manufacture the individual heads by capitalizing on semiconductor-like processing technology. As the requirements for magnetic head designs continue to stress narrower track widths, reduced flying heights above the disk surface, high disk rotational speeds, narrower gaps for improved resolution, and wider frequency response, thin film heads will continue to be attractive. Future advances in the magnetic recording industry will no doubt require miniaturization of the thin film head dimensions.
In a standard magnetic head recording system, the thin film head element is typically mounted along the rear edge of a block of non-magnetic material, commonly known as the slider. Sliders are designed such that the hydrodynamic pressure generated by a spinning disk causes the slider body to fly at a predetermined distance above the surface of the disk. During starting and stopping, the sliders rest in contact with the disk surface. In most cases, a plurality of skid pads are employed to provide an air-bearing surface during flying and provide contact points for the slider body during starting and stopping of the disk.
In high-performance disk drive units, it is generally desirable to maintain the head at a relatively low flying height so that a high signal-to-noise ratio amplitude can be achieved. Presently, magnetic transducers fly at nominal heights of approximately 5-8 microinches for a 4-6 gram head load.
One of the problems associated with high-performance recording heads is that as the flying height of the disk is reduced, asperities on the surface of the magnetic media may interact with the head. For example, when the head flies very near to the surface of the magnetic media, there is an increased chance that it may actually crash into large asperities projecting up from the surface of the disk. To avoid head crashes it is therefore highly desirable that the disk have an extremely smooth, asperity-free surface which is durable for both starting and stopping. Unfortunately, existing disk manufacturing processes make it virtually impossible difficult to achieve an asperity-free surface.
To overcome the problems inherent in the prior art, the present invention provides a specialized burnish head for conditioning the surface of the magnetic media. As will be seen, the novel head may be utilized for final smoothing operations of the disk surface. As the burnish head flies over the surface of the magnetic media, asperities are cut or cracked off, resulting in a highly-polished, smooth media surface.